The capture and analysis of images of people and objects in public spaces for security applications is well known in the art. Images can be captured as still images at regular intervals of time or continuously, as in the case of videos. The images are then stored for later reference to determine the identification of the people and objects in the space, or the images are stored and examined to identify when a person enters a secure area or to determine when and where objects are moved within the field of view of the image capture device. However, this approach may intrude upon the privacy of the people in the images and the owners of the objects because the images are typically captured without the consent of the people or owners. There is a desire to maintain the privacy of people and objects while enabling images to be captured and image information to be retained in a database for security, sponsored advertising and other uses.
United States Patent Application US20050271251 by Russell teaches a method of managing video data storage in a multi camera video surveillance system in an intelligent and automatic way. A series of rules are applied to the video data to determine the relative importance of different portions of the video data. The video data with the most importance is stored at higher resolution while less important data is deleted, compressed or archived. Image data is preserved in its entirety or partially.
European Patent Organization Patent Application WO2004/072897 by Goldberg discloses a method for collecting images of a patron in an entertainment venue that includes facial recognition of the patron's face within the images to simplify the storage and distribution of the images for a patron. In order to enhance the reliability of the facial recognition system, information about the patron including clothes, height, other associated people, use of glasses and jewelry, disposition of facial hair is also gathered. In the method described by Goldberg, a minimum of two images must be captured. The first image in WO2004/072897 serves as a reference to establish the person's identity and characteristic features. The second image is the desired image containing the person of interest. The information from the reference image is used to find a match in the second image set to identify the person, so information from both images has to be merged. One of the main objectives is to be able to retrieve images corresponding to a given person.
US 2004/0123131 discloses a method for processing image metadata for an image to be transmitted to a receiver. In accordance with the method, metadata access privileges are determined for the receiver and receiver metadata is produced from the image metadata based upon the metadata access privileges for the receiver. The receiver metadata is associated with the image. The metadata processing system and the method developed automatically controls the metadata that is associated with an image so that such metadata is not unintentionally transmitted to others. The image files are made available to receivers with all or limited metadata.
When electronic image files are manipulated with an image editor, i.e., software for editing or viewing electronic images, the image editor frequently strips away and discards any metadata that is recorded in the image file. The user is typically unaware that the metadata has been lost. U.S. Pat. No. 7,028,058 teaches a method of preserving metadata in an electronic image file that includes copying metadata into the image file from a metadata backup database after the metadata are removed from the electronic image file.
There are many images that are obtained with the consent of people such as employee pictures and driver's licenses that are stored in databases along with other information about the people that can be accessed under certain conditions. Similarly, there are images of people that are in the public domain that can be accessed without privacy concerns. However, using these images is very different from capturing images of people without their consent particularly when the images are subsequently utilized without their consent.
In all of the references mentioned above, all or part of the original image files are preserved with or without metadata. There remains a problem of maintaining privacy associated with retained images. None of the mentioned references remove all of the image pixels from the original data files (including the thumbnail images). Whenever any portion of an image file is retained, there is a possibility of people, objects, locations, businesses, brand names or situations to be identified leading to privacy issues. What is needed is a way of obtaining visual information while maintaining the privacy of people, objects, locations or situations in the imaged scene.